1. Field of the Invention
The present invention relates to locating systems of the type employing radiant energy signals and triangulation methods, and more particularly, to systems employing at least one mobile scanning platform such as, for example, a miniature aircraft, for issuing signals which evoke a response from a beacon attached to the subject of the search.
2. Description of the Prior Art
From time to time, it may be necessary or desirable to locate a person or an object which has disappeared or is out of sight or ready control of a person charged with monitoring the person or object. This is particularly true for people who have limited capacity to understand constraints on their freedom of movement and monitoring equipment employed to track them. For example, patients in health care facilities and children may possibly wander off and become lost to their care providers or other responsible parties. In other examples, whereabouts of those subject to house arrest programs must be monitored by civil authorities. Inanimate objects such as objects of great value or vehicles must be tracked to assure that no theft has occurred, or that the object or vehicle is where it should be.
It has become possible to implement remote locating systems with the advent of radio frequency communications and systems such as the Global Positioning System (hereinafter referred to as GPS) or an equivalent. Such systems are intended to be able to locate a missing person or object which carries a radio frequency transceiver. A person charged with authority or responsibility to monitor or periodically ascertain location of a person or object can employ a remote locating system to determine the location of the sought person or object despite vast distances which may exist between the sought person or object and the person monitoring the same. Additionally, great distances among components of apparatus of a locating system, the sought person or object, and the person monitoring the sought person or object may be easily overcome by a suitable locating system.
It would be possible to use a triangulation based system reliant upon the GPS. However, this may require objectionably large, sophisticated, or expensive components carried aboard the object or person being monitored. It is therefore desirable to provide a locating system which minimizes complication, cost, and bulk of components carried by or attached to the person or object being monitored as to location.
It further is desirable to be able to cover a wide geographic area. This is not feasible with scanners or other radio frequency devices mounted on buildings, towers, or the like. Rather, it is preferable to provide a scanner on aircraft. One advantage of aircraft based scanners is that such a location is best able to overcome attenuation of a radio frequency signal, as is frequently caused by physical objects which interfere with horizontal or nearly horizontal propagation of signals. An aircraft flying over a beacon benefits from relatively unimpeded xe2x80x9cdownward lookingxe2x80x9d receivers, and thus can detect signals which might otherwise go undetected.
The prior art has suggested locating systems which in part rely upon the GPS. Illustratively, U.S. Pat. No. 4,819,053, issued to Richard A. Halavais on Apr. 4, 1989, describes a single point locating system wherein a scanner is located on an aircraft. Similarly, U.S. Pat. No. 4,975,707, issued to Jordan R. Smith on Dec. 4, 1990, shows a system for locating kidnap victims wherein it is disclosed that aircraft may serve as the scanning platform.
U.S. Pat. No. 5,751,246, issued to Richard J. Hertel on May 12, 1998, features interrogation by aircraft and triangulation in a location system.
U.S. Pat. No. 6,067,018, issued to Joan M. Skelton et al. on May 23, 2000, shows a location system having body worn components, a portable component, and a base station.
U.S. Pat. No. 6,091,957, issued to John Pruett Larkins et al. on Jul. 18, 2000, illustrates child monitoring using triangulation.
The above schemes exemplify GPS based triangulation systems, but still cannot provide inexpensive, wide ranging scanning platforms which can upon demand seek out a signal beacon located at the sought person or object. Manned aircraft cannot necessarily be maintained in sufficient numbers and locations so as to be able to initiate a search on little notice. Also, use of manned aircraft, or even unmanned aircraft built on the scale of manned aircraft, entails safety considerations. For example, in severe weather conditions, aircraft are subject to disruption, such as being downed by downwardly moving air currents, being hit by lightning, and suffering other mishaps. Using such aircraft in highly populated areas entails well known hazards in the event of mishaps. There remains a need for a locating system which provides inexpensive ability to roam over a predetermined geographic area to locate a person or object.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention provides a versatile system for implementing triangulation searches using GPS satellites. The novel system shares some concepts with known triangulation search systems, and may for example employ well known processes to perform triangulation. A significant advance in the art of triangulation searches is the use of miniature, unmanned mobile sources of signals, which sources are referred to as scanning platforms, to initiate the search. To conduct a search according to the invention, a transceiver is attached to the object or person being monitored. A plurality of scanning platforms are utilized to originate or broadcast signals which will evoke a response from the transceiver. Next, the scanning platforms, working in tandem with other apparatus, utilize the GPS to establish both precise points in time and also locations of events occurring during a search. Fourthly, a central station receives data from the scanning platforms and calculates the sought location.
It will be appreciated, then, that two triangulation operations are conducted. The first determines location of mobile scanning platforms at the time each mobile scanning platform receives a response signal. The second triangulation operation actually determines location of the sought object utilizing determined locations of the mobile scanning platforms which received response signals.
Use of unmanned, preferably miniature, remotely piloted steerable vehicles, such as aircraft, as scanning platforms greatly facilitates coverage of a target search area. As employed herein, miniature signifies that the vehicle, regardless of whether it is an aircraft, boat, or land vehicle, is too small to carry a human occupant. At least one and optionally several or all of the scanning platforms are provided by miniature, remotely piloted vehicles. The remaining scanning platforms may be stationary, portable, or mobile.
As employed herein, stationary signifies that the scanning platform is fixed to the ground both when in use and also when not being used. A scanning platform mounted on a permanently fixed tower or on a building is exemplary. Portable signifies that the scanning platform is so configured as to be readily movable such as by towing or hauling to different sites, but lacks motive power and is not moving when being used. A scanner located on an unpowered, wheeled vehicle, or placed on a platform which by virtue of uncomplicated construction and limited weight and dimensions, is readily carried on or towed by a vehicle. Mobile will be taken to signify that the scanning platform is in motion either as a draft vehicle or under its own power when being used. Aircraft, wheeled and tracked self-powered vehicles, robots, and boats, whether manned or unmanned, are all examples of mobile scanning platforms.
In the preferred embodiment, the scanning platforms are provided by miniature, remotely piloted aircraft. Aircraft can easily fly over natural and artificial obstacles which would stymie or delay ground bound vehicles. Rugged terrain, buildings, bodies of water, forests, industrial facilities, roads, and the like offer little impedance to aircraft. Another significant advantage of aircraft is that in most cases they provide downward access to the sought person or object. This is especially advantageous in that it permits the person or object carried beacon to be low powered. This minimizes bulk, complexity, and cost of the transceiver associated with the monitored person or object.
The use of mobile scanning platforms such as aircraft also enables location to be acquired both by traditional triangulation and also by localizing. This is not possible when utilizing satellites and other general purpose vehicles which are not steerable at the discretion of the searcher. The use of miniature aircraft minimizes likelihood of catastrophic consequences should the aircraft be downed. This is a consequence of limited mass, speeds, and fuel capacity of miniature aircraft. Still another advantage of miniature aircraft is that a significant number thereof can be readily transported to a distant search site in a single vehicle.
The novel system may be utilized to track people, animals, and objects. For example, it may be utilized to thwart attempted kidnappings, to locate young or incapacitated persons who have wandered off, to track wildlife, or to monitor valuable property such as borrowed, leased, or rented equipment, objects on display or stored objects, and other objects which for any reason must be monitored as to whereabouts. The novel system can be rapidly deployed, and can locate sought subjects over great expanses with minimal intrusion upon the area of search.
Accordingly, it is one object of the invention to provide a locating system utilizing at least one miniature, remotely piloted vehicle as a scanning platform.
It is another object of the invention that the miniature, remotely piloted scanning platform be able to negotiate natural and artificial obstacles, and be able to provide direct, downwardly facing signal reception.
It is a further object of the invention that at least one scanning platform be steerable at the discretion of those conducting a search.
Still another object of the invention is to minimize adverse consequences of downing of an aerial scanning platform.
An additional object of the invention is to transport many scanning platforms to remote search sites readily and conveniently.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.